<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="stylesheet" href="./styles/index.css" />
    <title>Document</title>
  </head>
  <body>
    <div id="app" class="score-case">
      <div class="table">
        <table>
          <thead>
            <tr>
              <th>编号</th>
              <th>科目</th>
              <th>成绩</th>
              <th>操作</th>
            </tr>
          </thead>
          <!-- 列表 -->
          <tbody v-if="list.length > 0">
            <tr v-for="(item,index) in list" :key="item.id">
              <td>{{ index + 1 }}</td>
              <td>{{ item.subject }}</td>
              <td :class="{ red : item.score < 60 }">{{ item.score }}</td>
              <td>
                <a href="#" @click.prevent="del(item.id)">删除</a>
              </td>
            </tr>
          </tbody>
          <!-- 列表 - 空状态 -->
          <tbody v-else>
            <tr>
              <td colspan="5">
                <span class="none">暂无数据</span>
              </td>
            </tr>
          </tbody>

          <tfoot>
            <tr>
              <td colspan="5">
                <span>总分：246</span>
                <span style="margin-left: 50px">平均分：79</span>
              </td>
            </tr>
          </tfoot>
        </table>
      </div>
      <div class="form">
        <div class="form-item">
          <div class="label">科目：</div>
          <div class="input">
            <input
              type="text"
              placeholder="请输入科目"
              v-model.trim="subject"
            />
          </div>
        </div>
        <div class="form-item">
          <div class="label">分数：</div>
          <div class="input">
            <input
              type="text"
              placeholder="请输入分数"
              v-model.number="score"
            />
          </div>
        </div>
        <div class="form-item">
          <div class="label"></div>
          <div class="input">
            <button class="submit" @click="add()">添加</button>
          </div>
        </div>
      </div>
    </div>
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>

    <script>
      const app = new Vue({
        el: "#app",
        // 数据
        data: {
          // 列表
          list: [
            { id: 1, subject: "语文", score: 20 },
            { id: 7, subject: "数学", score: 99 },
            { id: 12, subject: "英语", score: 70 },
          ],
          // 科目
          subject: "",
          // 分数
          score: "",
        },
        // 方法
        methods: {
          // 删除
          del(id) {
            this.list = this.list.filter((v) => v.id !== id);
          },
          // 添加
          add() {
            // 添加前，空判断
            if (this.subject === "" || this.score === "") {
              return alert("请输入科目和分数");
            }
            // 添加数据
            this.list.unshift({
              id: Date.now(),
              subject: this.subject,
              score: this.score,
            });
            // 添加后，清空输入框
            this.subject = "";
            this.score = "";
          },
        },
      });
    </script>
  </body>
</html>
